Vacuum transfer system and method for food grade product

ABSTRACT

A vacuum transfer system for transferring food grade products. A biased ball in a cage with a substantially uninterrupted cage wall is utilized as a check valve. The ball may be biased by a weight to float in a predictable orientation relative to the cage. The biased ball assures that a certain portion of the ball will consistently engage with and aperture. The biased ball also minimizes chattering of the ball in the cage under high flow conditions.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.09/528,285, filed Mar. 17, 2000, now U.S. Pat. No. 6,425,408 which is acontinuation-in-part of U.S. application Ser. No. 09/061,408, filed Apr.16, 1998, now U.S. Pat. No. 6,058,949, issued May 9, 2000, which is acontinuation-in-part application of U.S. application Ser. No.08/632,558, filed Apr. 15, 1996, now U.S. Pat. No. 5,839,484, issuedNov. 24, 1998, which application claims the benefit of U.S. ProvisionalApplication No. 60/001,846, filed Aug. 2, 1995, hereby incorporated byreference in its entirety.

TECHNICAL FIELD

The present invention relates to the transfer of food grade product inand out of a vessel. More particularly, the transfer is effected bymeans of vacuum generated in the vessel.

BACKGROUND OF THE PRESENT INVENTION

Food grade product is presently transferred from one vessel to anothervessel by means of mechanical pumps that typically have rotatingimpellers or the like that effect the pumping of the food grade product.Food grade product may include for example eggs, liquid ingredients forthe making of ice cream, raw or processed milk, liquid feed forlivestock, liquid ingredients for the making of cheese, and the like.Reference herein is with respect to the transfer of raw milk from aholding tank at the production site to a vehicle tank for the transferof the raw milk to a processing plant. The vehicle may be either a truckor a trailer, as depicted, that is transported by a tractor. Thoseskilled in the art will recognize that the same principles as aredescribed herein are applicable to other transfers of food grade productfrom a first vessel to a second vessel. For example, the transfer of rawmilk from the truck or trailer-mounted tank to a tank in the processingplant may be effected by the present invention. Additionally, thetransfer of food grade product from a first vessel in the processingplant to a second vessel in the processing plant may be effected by thepresent invention.

Bulk milk pick-up from the point of origin as we know it today, consistsof a truck or trailer-mounted stainless steel insulated transport tank.This transport tank is at atmospheric pressure and is therefore notoperated at a vacuum and not operated at a pressure greater thanatmospheric pressure. In order to effect the transfer of the raw milkform the holding tank to the transport tank, both the holding tank andthe transport tank are vented to the atmosphere during the transferoperations.

The amount of time spent transferring the raw milk or other food gradeproduct is a major cost item. With respect to the transport of raw milk,this time dictates the number of drivers and transport trucks needed toservice a specified route of customers. The size of dairies has beenever increasing and the distance between dairies on a route is alsoincreasing. Dairy herds of more than two hundred animals are notconsidered big any more. This increase in size has required that thesize of the holding tanks at the dairy be greatly increased. In thepast, a five hundred gallon holding tank was considered adequate. Theholding tank now may hold several thousand gallons of raw milk. Thesheer size of the holding tanks has greatly increased the transfertimes. During the transfer of the milk from the holding tank to thetransport tank both the driver and the truck are idle, greatlyincreasing the cost of transporting the milk from the dairy top theprocessing plant.

The milk is presently pumped from the holding tank at the farm (or othersite of pick-up) to the transport tank by several different types ofmechanical food grade impeller pumps. Presently, the pump that will pumpthe greatest volume of milk is a hydraulic driven stainless steel gearpump that will pump 230 gallons per minute. The cost of this unit isapproximately $15,000.00 installed. To transfer two thousand gallons ofmilk product using this pump takes in excess of eight minutes.

The problem to the purchaser of the aforementioned pump, aside from thecost, is a problem that is years old. Every time milk is forced throughpump impellers, the bacteria count in the milk is multiplied, and themolecular structure of the raw milk product is broken down. The moreagitation that is caused by the pump, the greater the increase in thebacteria level and the greater the molecular breakdown that results inthe milk. The increase in the bacteria level can pose a serious healthconcern. Additionally, the membrane around the fat molecule is broken bythe pump agitation, resulting in undesired acidity in the milk. Themolecular breakdown results in a decrease in the amount of the milk thatcan be used as an ingredient in dairy products, such as ice cream andcheese. The non useable portion is disposed of as the whey that is a byproduct of making the dairy products and is useful primarily for animalfeed. The animal feed is sold at substantially reduced cost as comparedto products for human consumption that could otherwise have beenproduced, thereby reducing the potential return from a quantity of rawmilk.

An additional health concern is the cleanliness of the pump used for thetransfer of the food grade product from vessel to vessel. Recently, anincident of salmonella infection being passed on to the ultimateconsumer as a result of the lack of cleanliness of the transport vesselhas been reported. It is a requirement that the transfer pumps bedisassembled at least daily and sanitized to preclude such a problemfrom occurring. Sanitizing the impellers of the pump is a difficulttask. Only a small amount of the salmonella organism left in theimpeller can taint a subsequent load of food grade product that ispumped into the vessel.

With the increased size of dairy holding tanks comes the need toincrease the volume load of the transport tanks that are mounted on asingle truck chassis. Many states have stringent regulations governingthe gross weight of vehicles using the public roads. With the increasedtransport tank volume and the weight of milk product that is beingtransported, there is a need to keep the transport tank weight to aminimum in order to maximize the milk volume that may be legallytransported.

It would be a decided advantage in the food products industry to be ableto more rapidly transfer food grade product from one vessel to anotherand at the same time minimize the mechanical agitation of the food gradeproduct that results from such transfer to minimize the bacteria countincrease in the food grade product and to minimize the molecularstructure breakdown that also results form the mechanical agitation.Further, it would be an advantage to have a transfer system for foodgrade product that was more easily sanitized.

SUMMARY OF THE INVENTION

Using the vacuum system of the present invention for transferring rawmilk, the milk flows at a rate in excess of 2,000 gallons per minutethrough a six inch diameter conduit while transferring milk from theholding tank and loading the transport tank, thereby reducing theloading time at the pick-up point by a factor of almost ten as comparedto the fastest current means. This is accomplished using existing pipingfrom the holding tank to the transport tank. Such piping is typicallyeither two and a half inch pipe or three inch pipe. Coupled with thefaster transfer time are a better load environment for the raw product,a significant lowering of the initial costs of the pumping system, and areduction in clean-up and re-sanitizing time of the system as the rawproduct never touches any pumping mechanism, but is transferred solelythrough piping. No additional pump is necessary to effect the transferof the food grade product. Additionally, from a health standpoint, thereis no deleterious agitation of the food grade product heretoforeassociated with pumping by means of high speed impeller rotation.Further, the present invention includes a cleaning and sanitizationsystem for cleaning and sanitizing both the tanks and the vacuum lines.

The present invention includes a cleaning apparatus for cleaning andsanitizing a tank, the tank for holding liquid food grade product, theliquid food grade product being transferred into and out of the tank bymeans of vacuum, the tank having a vacuum transfer system fortransferring liquid food grade product includes apparatus for cyclicallyalternating a flow of cleaning fluid between the tank and the vacuumtransfer system. The present invention is further, a method for cleaningand sanitizing a tank for holding liquid food grade product, the liquidfood grade product being transferred into and out of the tank by meansof vacuum, the tank having a vacuum transfer system for transferringliquid food grade product. The method includes the steps of:

(a) providing a cleaning fluid to a fluid inlet;

(b) cyclically alternating the flow of cleaning fluid between the tankand the vacuum transfer system; and

(c) venting the cleaning fluid from the tank and from vacuum transfersystem;

whereby the tank and the vacuum transfer system are cleaned andsanitized during a single cleaning program having a selected series ofrinse, cleaning and sanitizing cycles.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional side view of the vacuum transfer unit of thepresent invention as taken along lines 1—1 of FIG. 2;

FIG. 2 is a side view of a vehicle with tandem transport tanks mountedthereon and a primary shutoff unit mounted in each of the transporttanks;

FIG. 3 is a side view of a tank vehicle with tandem transport tanksmounted thereon and a second embodiment of the vacuum transfer unit ofthe present invention mounted in each of the transport tanks with aportion of one tank broken away to reveal the vacuum unit mountedtherein;

FIG. 4 is perspective view of the plumbing and valving of the rearmostvacuum transfer unit as depicted in FIG. 3;

FIG. 5 is an elevational view of the vacuum transfer unit with portionsthereof broken away;

FIG. 6 is an elevational view of the vacuum generation unit mounted onthe tank vehicle;

FIG. 7 is an elevational view of the interior of the rear compartment ofthe tank vehicle;

FIG. 8 is a side view of a tank vehicle with tandem transport tanksmounted thereon and a vacuum transfer unit of the present inventionmounted in each of the transport tanks with a portion of one tank brokenaway to reveal the vacuum unit mounted therein;

FIG. 9 is perspective view of the plumbing and valving of the rearmostvacuum transfer unit as depicted in FIG. 8;

FIG. 10 is an elevational view of the interior of the rear compartmentof the tank vehicle;

FIG. 10a is an enlarged elevational view of the control panel depictedin FIG. 10;

FIG. 11 is a sectional view of a plunger-type valve as used in thepresent invention;

FIG. 12 is a sectional side view of another embodiment of the vacuumtransfer unit of the present invention;

FIG. 12a is a detail sectional side view of the embodiment depicted inFIG. 12; and

FIG. 13 is a sectional side view of the embodiment of the vacuumtransfer unit of FIG. 12 depicting operational movements in phantom.

DETAILED DESCRIPTION OF THE DRAWINGS

The vacuum transfer unit of a first embodiment of the present inventionis shown generally at 10 in FIGS. 1 and 2. A tank vehicle 12 has aunitary transport tank 14 mounted thereon. In the depiction of FIG. 2,the transport tank 14 is divided into two separate tanks 14 a, 14 b. Asingle tank 14 configuration could be used as well. Although the presentinvention is described with respect to a transport tank, the vacuumtransfer unit 10 is useful for effecting transfer into and from anyvessel.

The transport tank 14 is preferably constructed of 10 gauge stainlesssteel, (the same material and thickness as some non-vacuum tanks oftoday) and is reinforced with stainless steel hat channel rings and deepdish heads to keep the tank 14 from implosion during periods of highvacuum in the tank 14. The cross section of the hat channels issubstantially similar to the cross section of a hat having a crown andcircular brim. Insulation is placed between the channels and apreferably stainless steel outer shell is affixed to the outer margin ofthe channels.

Each transport tank 14 a, 14 b has a product inlet/outlet 16 a, 16 bassociated therewith. The product inlet/outlet 16 a, 16 b is typicallydisposed at a low point in the transport tank 14 a, 14 b so that thetransport tank 14 a, 14 b is filled from the bottom thereof and emptiedfrom the bottom thereof. As depicted, a holding tank 18 is positionedadjacent to the tank vehicle 12. The holding tank 18 has two outlets 20.Each such outlet 20 is fluidly coupled to one of the productinlet/outlets 16 a, 16 b by a flexible conduit 22. The flexible conduit22 is typically stored on the tank vehicle 12 and connected to theholding tank 18 at the product pickup site. The flexible conduit 22 mayhave a diameter between two and a half inches and six inches. Theholding tank 18 has a inlet/vent 24 through which food product istransferred into the holding tank 18 and by which means the holding tank18 is vented during removal of food product therefrom.

A vacuum generation unit 30 is mounted on the tank vehicle 12. Thevacuum generation unit 30 may be power take off (PTO) driven from thetractor (not shown) that is utilized to pull the tank vehicle 12. Thevacuum generation unit 30 is comprised of a pump 32, a filter 34, alubricant trap 36, and vacuum lines 38. The pump 32 is preferably a vanetype pump. The filter 34 isolates the pump 32 from any foreign material,including product, that may be passing through the vacuum lines 38. Alubricant is typically injected into the pump to lubricate theinterfaces between the vanes (not shown) and the inner surface (notshown) of the pump case of pump 32. The lubricant trap 36 is downstreamof the pump 32 and is utilized to entrain lubricant that is carried withthe exhaust from the pump 32. The lubricant so entrained may be thenrecycled back to the pump 32 to further lubricate the vanes thereof.

Referring to FIG. 1, a manway cover 50 is hinged at one side 51 andsealed at the perimeter thereof to the outer surface of the tank 14. Themanway cover 50 is generally circular and is contoured to conform to thesurface of the outer shell of the tank 14. The manway cover ispreferably constructed of stainless steel.

A manway opening 52 is centrally disposed in the manway cover 50. Themanway opening 52 is preferably cylindrical in shape, having a lowermargin that is shaped to conform to the contour of the manway cover 50.The upper margin of the manway opening 52 has a sealing lip 54 definedthereon. The manway opening 52 is preferably a circular opening having adiameter of approximately two feet to make it possible for a person toenter the tank 14 through the manway opening 52, if needed.

The vacuum transfer unit 10 is depicted as being inserted from the topwithin the manway opening 52. The vacuum transfer unit 10 is sealinglyretained within the manway opening 52 by quick release clamp 56 affixedto the sealing lip 54. The quick release clamp 56 is preferably acircular ring that encloses the sealing lip 54 and is held in sealingengagement therewith by an over center lock (not shown). The vacuumtransfer unit 10 may be readily removed from the manway opening 52 inorder to perform required cleaning and sanitizing by releasing the quickrelease clamp 56 and pulling the vacuum transfer unit 10 upward, clearof the manway opening 52.

Vacuum transfer unit 10 is fully constructed of stainless steel materialin order to meet the requirements for storing and transferring foodgrade product.

Vacuum transfer unit 10 has a low profile vacuum transfer dome 60 thatforms the upper surface thereof. A float ball cage 62 depends from thevacuum transfer dome 60 and is attached thereto by float ball cagefastening clips 64. The float ball cage 62 has a plurality of apertures66 defined therein that permit the free flow of food product in and outof the float ball cage 62, while retaining the stainless steel floatball 68 therein. The float ball 68 is generally spherical in shape andis sealed having a quantity of air trapped therein, such that the floatball 68 will float on top of the liquid food grade product that risesinto the float ball cage 62. When there is no liquid food grade productin the float ball cage 62, the float ball 68 drops to the bottom of thefloat ball cage 62 and rests there.

A primary pipe 70 is disposed within the vacuum transfer dome 60 andprovides a fluid passageway through vacuum transfer dome 60 from thefloat ball cage 62. The lower margin of the primary pipe 70 has agenerally circular beveled rubber float seal seat 72 disposed thereon.The float seal seat 72 is beveled inward, such that the lower mostdiameter of the beveled portion is greater than the uppermost, innerdiameter of the beveled portion, as depicted in FIG. 1. The lowermostdiameter of the float seal seat 72 is less than the diameter of thefloat ball 68. The float seal seat 72 is designed to establish a fluidlysealing engagement with the outer surface of the float ball 68 when thefloat ball 68 has risen into the float seal seat 72 and is centeredthereon. The upper margin of the primary pipe 70 is coupled to astainless steel tee 74 by a stainless steel nut 76.

A first outlet of tee 74 is coupled to a manually operated butterflyvalve 80 by a stainless steel nut 76. An external handle 82 is providedon the butterfly valve 80 to manually open and close the butterfly valve80 as desired. A removable, disposable intake air filter 84 is attachedto the butterfly valve 80. The butterfly valve 80 connects the interiorof the tank 14 with the outside atmosphere when the butterfly valve 80is in the open configuration. The butterfly valve 80 could be replacedwith another type of U.S.D.A. approved valve, such as a ball type orplug type valve.

The second branch of the tee 74 is coupled by a stainless steel nut 76to a one way check valve 86. The check valve 86 is biased in the closedconfiguration so that no fluid flow is possible through the check valve86. When in the open configuration, the check valve 86 permits the flowof fluid only from right to left as depicted by arrow 87 in FIG. 1. Inorder to open check valve 86, a vacuum of less than ten inches ofmercury, but preferably three to five inches of mercury must be appliedat the left side of check valve 86, as depicted in FIG. 1. The necessaryvacuum to open the check valve 86 is applied to the left side of thecheck valve 86 by the vacuum generation unit 30 when the vacuumgeneration unit 30 is in operation. In all cases when the vacuumgeneration unit 30 is not in operation, the check valve 86 is biased inthe closed configuration, isolating the vacuum line 38 from the tank 14.

Check valve 86 is fluidly coupled by a stainless steel nut 76 to abackup butterfly valve 88. Butterfly valve 88 is coupled to actuator 90.Actuator 90 may be either electrically or pneumatically actuated.Actuation of actuator 90 is preferably synchronized with the activationof the vacuum generation unit 30, such that the butterfly valve 88 isopen when the vacuum generation unit 30 is operating and the butterflyvalve 88 is closed when the vacuum generation unit 30 is not operating.The butterfly valve 88 is fluidly coupled to vacuum line 38 and therebyto the vacuum generation unit 30.

Upon activation, the vacuum generation unit 30 draws a vacuum in thevacuum lines 38. Such vacuum may selectively affect either or both ofthe vacuum transfer units 10, as depicted in FIG. 2, depending on theconfiguration of the aforementioned valves of the two vacuum transferunits 10.

The vacuum transfer unit of a second embodiment of the present inventionis shown generally at 10 in FIGS. 3-7. Similar numerals depict similarcomponents in the description of the second embodiment as in thedescription of the first embodiment of the vacuum transfer unit 10.

A tank vehicle 12 has a unitary transport tank 14 mounted thereon. Tofacilitate the maintenance and cleaning of the vacuum transfer unit 10and the tank 14, a ladder 11 and a gangway 13 are provided to affordaccess thereto by an operator as needed. In the depiction of FIG. 2, thetransport tank 14 is divided into two separate tanks 14 a, 14 b by awall 15. A single tank 14 configuration could be used as well. Eachtransport tank 14 a, 14 b has a product inlet/outlet 16 a, 16 b disposedon the front wall 17 of the rear compartment 19 of the tank vehicle 12,as depicted in FIG. 7. A flexible conduit 22 is stored in the rearcompartment 19 for connecting to the holding tank 18.

Referring to FIG. 3, a manway cover 50 is fluidly coupled to each tank14 a, 14 b. Each manway cover 50 is hinged at one side and sealed at theperimeter thereof to the outer surface of the tank 14. The manway cover50 is generally circular and is contoured to conform to the surface ofthe outer shell of the tank 14. The manway cover 50 is preferablyconstructed of stainless steel and is designed to accommodate access tothe tank 14 by an operator, primarily to clean the inside of the tank14.

A vacuum generation unit 30 is mounted on the tank vehicle 12 in acabinet 31. The vacuum generation unit 30 is self contained, in that itcontains its own power generation capability and the vacuum generationunit 30 may be configured to either load product into the tank 14 orunload product from the tank 14. This capability ensures that there isan on board capability to load and unload using the components of thepresent invention, without resort to an external source of power foreither loading or unloading the tanks 14 a, 14 b. This is an importantfeature so that the tanks 14 a, 14 b can be loaded or unloaded at anyfacility without the need for specialized pumping capability at thefacility adapted to be compatible with the vacuum transfer unit 10.

The vacuum generation unit 30 is comprised of a pump 32, a motor 100, asecondary shutoff 102, and vacuum lines 38. The pump 32 is preferably alobe type blower or a rotary vane type air compressor. The pump 32 ispowered by a rotary drive shaft 103 coupled to the motor 100. The pump32 has an air line 104 that fluidly couples the pump 32 to the secondaryshutoff 102. A four way change over valve 106 is disposed between theair line 104 and the pump 32 and is mounted on the pump 32. The four waychange over valve 106 is utilized to selectively alter the fluidcoupling from the pump 32 to the air line 104 such that a vacuum isdrawn through the air line 104 or a fluid, preferably air, is forcedunder pressure through the air line 104. The configuration of the fourway change over valve 106 is selectable by an operator utilizing a twoposition valve handle (not shown). By this means, the pump 32 is used toeither draw a negative pressure in the vacuum line 38 or to charge thevacuum line 38 under a positive pressure. Four way change over valve.

The motor 100 is preferably a gas internal combustion engine ofapproximately eighteen bhp. The motor 100 preferably has a battery andelectric start capability that is selectable on an operator's panel 108.The operator's panel 108 also has a throttle for control of the outputof the motor 100 as desired. The motor 100 is designed to operate at anidle rpm. When at idle rpm, the motor 100 is disengaged from the pump32. The throttle can then be advanced to a greater rpm that activates aclutch engagement to the pump 32 and causes rotational driving of thepump 32 by the motor 100.

The secondary shutoff 102 is a vessel that functions as a shutoff toisolate the pump 32 from any liquid that might be drawn from thesecondary shutoff 102 through the air line 104. The primary shutofffunction is accomplished with the vacuum transfer unit 10. Accordingly,the secondary shutoff 102 has a float valve (not shown) disposed in thesecondary shutoff 102 that is interposed between the vacuum line 38 andthe air line 104 such that, when the liquid in the secondary shutoff 102rises to a certain level in the secondary shutoff 102, the float valveengages a seat and the flow of fluid to the pump 32 is interrupted. Thisprevents liquid from entering the pump 32, which could result in damageto the pump 32. A drain is disposed in the bottom of the secondaryshutoff 102 to remove accumulated liquid. The secondary shutoff 102 hasa valved drain 110 disposed in the bottom for the draining of liquidtherefrom as desired.

Referring to FIGS. 3-5, the vacuum transfer unit 10 is depicted as beinginserted from the top within a collar 112. The collar 112 is affixed tothe tank 14 as by welding. The vacuum transfer unit 10 is sealinglyretained within the collar 112 by quick release clamp 56 removablyaffixed thereto. The quick release clamp 56 is preferably a circularring that encloses a lip 54 that forms the upper margin of the collar112 and is held in sealing engagement therewith by an over center lock(not shown). The vacuum transfer unit 10 may be readily removed from themanway opening 52 in order to perform required cleaning and sanitizingby releasing the quick release clamp 56 and pulling the vacuum transferunit 10 upward, clear of the collar 112.

The vacuum transfer unit 10 has a low profile vacuum transfer dome 60that forms the upper surface thereof. A float ball cage 62 depends fromthe vacuum transfer dome 60. The float ball cage 62 has a plurality ofapertures 66 defined therein that permit the free flow of food productin and out of the float ball cage 62, while retaining the stainlesssteel float ball 68 therein.

A primary pipe 70 is disposed within the vacuum transfer dome 60 andprovides a fluid passageway through vacuum transfer dome 60 from thefloat ball cage 62. The lower margin of the primary pipe 70 has agenerally circular beveled rubber float seal seat 72 disposed thereon.

The upper margin of the primary pipe 70 is coupled by a stainless steelnut 76 to a butterfly valve 88. The butterfly valve 88 is coupled toactuator 90. Actuator 90 may be either electrically or pneumaticallyactuated and acts to open and close the butterfly valve 88. Actuation ofactuator 90 is preferably synchronized with the activation of the vacuumgeneration unit 30 and is controlled by means of communication lines 114by manually operated switches 116 a, 116 b, with the switch 116 a beingcoupled to the actuator 90 on the vacuum transfer unit 10 in the tank 14a and the switch 116 b being coupled to the actuator 90 on the vacuumtransfer unit 10 in the tank 14 b. The communication lines 114 arepreferably either electric or pneumatic. The butterfly valve 88 coupledto the tee 74 by a nut 76.

The tee 74 has a vent outlet 118 and a vacuum outlet 120. The ventoutlet 118 is connected to the vent line 122 by a nut 76. The vent line122 is coupled to a manually operated butterfly valve 80, as depicted inFIG. 7. An external handle 82 is provided on the butterfly valve 80 tomanually open and close the butterfly valve 80 as desired. The butterflyvalve 80 is connected to a removable, disposable intake air filter 84that is located in the rear compartment 19. The butterfly valve 80connects the interior of the tank 14 with the outside atmosphere whenthe butterfly valve 80 is in the open configuration.

The second branch of the tee 74 is coupled by a stainless steel nut 76to a check valve 86. The check valve 86 is biased in the closedconfiguration so that no fluid flow is possible through the check valve86. When in the open configuration, the check valve 86 permits the flowof fluid only from right to left as depicted by arrow 87 in FIG. 1. Inorder to open check valve 86, a vacuum of less than ten inches ofmercury, but preferably three to five inches of mercury must be appliedat the left side of check valve 86. The necessary vacuum to open thecheck valve 86 is applied to the left side of the check valve 86 by thevacuum generation unit 30 when the vacuum generation unit 30 is inoperation.

Cleaning lines 130 are fixedly coupled to the tank 14. An inlet 132 isdepicted in FIG. 4. The inlet 132 provides a coupling to an exteriorsource of cleaning solution that may be introduced under pressure to thetank 14. A valve 136 that is manually operated by handle 136 is disposedin the cleaning lines 130 so that the cleaning solution may beintroduced to either or both of the tanks 14 a, 14 b, as desired. Aspray-ball type nozzle 138 is coupled to the cleaning lines 130 and isdisposed within the tank 14 for dispensing the cleaning solution inorder to flush the tank 14.

Upon activation, the vacuum generation unit 30 draws a vacuum in thevacuum lines 38. Such vacuum may selectively affect either or both ofthe vacuum transfer units 10 as depicted in FIGS. 2 and 3 by selectivelyconfiguring appropriate valves in the vacuum lines 38.

There are essentially three operating conditions for the presentinvention. Referring to the embodiment of FIGS. 1 and 2, the first suchoperating condition is transferring food product from the holding tank18 into the transport tank 14 a, 14 b. To effect such transfer by meansof vacuum, (a) the tank into which the food grade product is to betransferred, transport tank 14 a, 14 b in the present example, must beisolated from the atmosphere, (b) the two tanks must be fluidlyconnected, as by conduit 22 in the present example, and (c) the tankbeing transferred from, here holding tank 18, must be vented to theatmosphere as at inlet/vent 24. This creates a fluid flow path from thevacuum generation unit 30 through the tanks 14 a, 14 b, and holding tank18 to the atmosphere at inlet/vent 24 with the food grade productdisposed between the source of the vacuum and the atmosphere. Generationof the vacuum by vacuum generation unit 30 will draw the food gradeproduct toward the source of the vacuum and displace the food gradeproduct in the holding tank 18 with air drawn in through the inlet/vent24.

In order to establish the requisite fluid flow path as indicated aboveto effect such transfer, the vacuum transfer unit 10 is configured withthe manually operated butterfly valve 80 maintained in its closedposition. This isolates the tank 14 from the atmosphere. The vacuumgeneration unit 30 is activated and at the same time a signal is sent tovalve actuator 90 to open the butterfly valve 88. When the butterflyvalve 88 is in the open configuration, the check valve 86 is in flowcommunication with the vacuum generation unit 30 and vacuum generated bythe vacuum generation unit 30 acts upon the check valve 88. At such timeas the vacuum generation unit 30 applies a three to five inch of mercuryvacuum to the check valve 86, check valve 86 opens.

With respect to the embodiment of FIGS. 3-7, the manually operatedbutterfly valve 80, which is located in the rear compartment 19, ismaintained in its closed position. The appropriate switch 116 a, 116 b,also located in the rear compartment 19, is selected to actuate valveactuator 90 to open the butterfly valve 88 for the desired tank 14 a or14 b. Prior to energizing the pump 32, the four way change over valve106 must be in the position such that the pump 32 is drawing a vacuum inthe vacuum lines 38.

At this point a vacuum is drawn in the transport tank 14 a, 14 b. Thevacuum is approximately 22-25 inches Hg. The vacuum is transmitted tothe transport tank 14 a, 14 b via primary pipe 70 and the plurality ofapertures 66 defined in the float ball cage 62. The vacuum does notaffect the float ball 68 and the float ball 68 remains disposed on thebottom of the float ball cage 62.

As the air in the transport tank 14 a, 14 b is substantially exhaustedby the vacuum generation unit 30, the vacuum acts through the conduit 22on the food grade product that is stored in the holding tank 18. Thisvacuum draws the food product from the holding tank 18 through theflexible conduit 22 and into the transport tank 14 a, 14 b at a veryhigh rate of flow without the agitation caused by a pump impeller. Asthe food grade product is drawn from the holding tank 18, air is drawninto the holding tank 18 through the open inlet/vent 24.

The holding tank 18 may have a lesser capacity than the tank 14. In thisinstance, the holding tank 18 will be emptied prior to fully filling thetransport tank 14 a, 14 b. The operator then observes the emptying ofthe holding tank 18 and shuts off the vacuum generation unit 30. At thesame time as deactivation of the vacuum generation unit 30, a signal issent to the valve actuator 90 closing the butterfly valve 88.Additionally, removal of the vacuum from left side of the check valve 86that is the result of deactivating the vacuum generation unit 30 causesthe check valve 86 to close, sealing the vacuum transfer unit 10.

In the instance in which the food grade product that is transferred tothe transport tank 14 a, 14 b causes he transport tank 14 a, 14 b tobecome filled prior to completely transferring the food grade productfrom the holding tank 18, the stainless steel float ball 68 rises as thefood grade product flows into the float ball cage 62 and sealinglyengages the float seat 72. In such condition, the vacuum generation unit30 is incapable of applying a vacuum to the transport tank 14 a, 14 b.The operator then deactivates the vacuum generation unit 30. Thebutterfly valve 88 and check valve 86 are then closed as previouslyindicated.

The second operating condition is in transport of food product. In thiscondition, the manually operated butterfly valve 80 is maintained in itsclosed position. The check valve 86 is closed due to the fact that novacuum is being applied thereto by the vacuum generation unit 30. If thetransport tank 14 a, 14 b is overly full, the float ball 68 will also incontact with the float seat 72, preventing the surge of foam or foodgrade product into the primary shut off unit 10. In practice, it is rarethat the transport tank 14 a, 14 b will be so full as to cause thiscondition and the float ball 68 is then floating free of float seat 72.

The third operating condition is emptying the transport tank 14 a, 14 b.In this operating condition, as depicted in the embodiment of FIGS. 1and 2, the operator must ascend to the top of the tank 14 a, 14 b andmanually open the butterfly valve 80 by actuation of the handle 81 tovent the transport tank 14 a, 14 b. This same action is accomplished inthe rear compartment 19 in the embodiment of FIGS. 3-7. The check valve86 and butterfly valve 88 are maintained in their closed positions. Aconduit similar to conduit 22 is connected to the product inlet/outlet16 a, 16 b and pumps in the plant that is receiving the food product areactivated to empty the transport tank 14 a, 14 b. The plant may also beequipped with a vacuum transfer apparatus in accordance with the presentinvention. In such case, a vacuum generation unit similar to vacuumgeneration unit 30 and a vacuum transfer unit 10 are operably coupled toa receiving tank within the processing plant and removal of the foodgrade product from the transport tank 14 a, 14 b is accomplished in amanner similar to the manner described above for transferring the foodgrade product from the holding tank 18 to the transport tank 14 a, 14 b.

With respect to the embodiment of FIGS. 3-7, the tanks 14 a, 14 b may beemptied by utilizing the vacuum generation unit 30. In this case, thefour way change over valve 106 must be in the position such that thepump 32 is pressurizing the vacuum lines 38. The preferred vacuumgeneration unit 30 is capable of imposing a pressure of approximatelyten lb/sq in on the product in the tank 14 a, 14 b. This pressure isconveyed by means of vacuum lines 38 through the vacuum transfer unit10. The pressure forces the product out of the product inlet/outlet 16a, 16 b. Alternatively, in the instance where the plant to which theproduct is being transferred has a pressurization capability, the plantpressurization unit may be connected to the vent line 122 to pressurizethe product in the tank 14. This is accomplished by removing the filter84 and connecting a conduit from the plant pressurization unit to thebutterfly valve 80. The butterfly valve 80 is then opened. The butterflyvalve 88 must also be opened by activating the actuator 90 by means ofthe switch 116 a, 116 b. In this configuration, the one way check valve86 prevents the pressure from pressurizing the vacuum lines 38.

As previously indicated, the cleanliness and sterility of the tanks 14and associated plumbing is a paramount need. Further, there is a need toperform the necessary cleaning in as timely a manner as possible.Typically, a facility that receives the transported food grade producthas one or more cleaning bays. At the end of each work day after thetanks 14 have been unloaded for the last time, the tank vehicle 12 ispositioned in the cleaning bay for cleaning of the tank 14.

The cleaning is done in a manner prescribed by governmental bodies,primarily the U.S. Department of Agriculture. A typical cleaning andsanitizing cycle may extend for as much as 25 minutes. The cleaningprogram typically proceeds through a rinse cycle, a wash cycle, a rinsecycle, a wash cycle, a rinse cycle, and a sanitizing cycle. The cleaningbay has a cleaning unit that includes a hose hook-up for the tank 14.The cleaning unit operates at a certain pressure and volume and cyclesthrough the cleaning program, changing the liquid provided to the tank14 depending on the particular cycle that the cleaning program ispresently operating in.

In addition to cleaning and sanitizing of the tanks 14, the vacuumtransfer unit 10 of the present invention includes vacuum lines thatmust also be cleaned and sanitized since the vacuum lines and the vacuumtransfer unit 10 are exposed to the food grade product during transferoperations. In order to efficiently clean and sanitize both the tanks14, the vacuum transfer units 10, and the vacuum lines associated withthe vacuum transfer unit 10, it is desirable to clean the entire system,tanks 14, vacuum transfer units 10, and vacuum lines, during a singlecleaning and sanitizing operation. The cleaning system 200 of thepresent invention provides this single operation cleansing both thetanks 14 and the associated vacuum lines.

The cleaning system 200 is shown generally in FIGS. 8-11. The cleaningsystem 200 is an improved version of the previously described cleaningapparatus. Like numerals indicate like components in the cleaning system200 and in the previously described cleaning apparatus. Referring toFIGS. 8 and 9, the detail depicted in FIG. 9 with reference to the reartank 14 b is substantially duplicated with reference to the forward tank14 a. The vacuum line 122 and the cleaning line 130 both extend to therear of the tank 14 b and are plumbed into the rear compartment 19.

A control panel 206 disposed in the rear compartment 19 controls theoperation of cleaning system 200. The control panel 206 has two switches202 a and 202 b mounted thereon. In a preferred embodiment, the switches202 a, 202 b are three-position switches, being selectable between aload position, an off position, and a clean position, as depicted inFIG. 10a. The switches 202 a, 202 b are communicatively coupled to atimer 212. The timer 212 is communicatively coupled to the two valves 88(for tanks 14 a and 14 b) by means of communication lines 114 a and 114b. Additionally, the switches 202 a, 202 b are respectively coupled tothe valves 136 (for tanks 14 a and 14 b) by means of communication lines204 a and 204 b. The timer 212 is additionally communicatively coupledto a clean valve 214 by means of a cleaning communication line 208 andto a vacuum valve 216 by means of a vacuum communication line 210.

Referring to FIG. 10, the cleaning line 130 is fluidly coupled to theclean valve 214. The vacuum line 122 is fluidly coupled to the vacuumvalve 216. A T-connector 218 fluidly couples the clean valve 214 and thevacuum valve 216. A filter 222 is disposed on a fitting 220 of theT-connector 218. It should be noted that during cleaning operations, thefilter 222 is removed to expose the fitting 220 for connection to theline from the cleaning system in the cleaning bay.

In a preferred embodiment, the valves 88, 134, 214, and 216 are allplunger type valves as depicted at 224 in FIG. 11. Preferably, theplunger valve 224 is operated pneumatically through a pneumatic inlet226. Air pressure applied through the pneumatic inlet 226 acts to unseatthe plunger 228 to move the plunger 228 to its open disposition asdepicted in FIG. 11. In the open disposition of the plunger 228, thefluid inlet 230 is fluidly coupled to the fluid outlet 232.

When pneumatic pressure is removed from the pneumatic inlet 226, thereturn spring 234 acts on the plunger shaft 236 to return the plunger228 to a sealed engagement with the seat 236. This action fluidlyuncouples the fluid inlet 230 from the fluid outlet 232.

An advantage of the plunger valve 224 as depicted in FIG. 11 is thatduring cleaning operations, the wetted portions of the plunger valve 224have been determined to be adequately cleaned and sanitized withoutremoval of any component of the plunger valve 224. Plunger valves ofthis type are available from Waukesha Cherry-Burrel, Corp., Delevan,Wis.

In a cleaning operation, the filter 220 is removed from the fitting 220.A suitable hose is connected to the fitting 220 from the cleaning systemin the cleaning bay. Additionally, drain hoses are coupled to theproduct inlet/outlet 202 a, 202 b of the tanks 14 a and 14 b,respectively. Further, a drain hose is connected to the drain 110 of thesecondary shutoff 102. The switches 202 a and 202 b are rotated to theclean position. This activates the timer 212.

The timer 212 synchronizes the opening and closing of the valves 88,134, 214, and 216. In a preferred embodiment, the timer 212 alters theconfiguration of the aforementioned four valves every ten seconds duringa cleaning operation. The duration of time between the configurationchanges may be altered to match the duration of the various cycles ofthe cleaning operation as determined by the cleaning system of thecleaning bay. A cleaning system that has relatively high fluid flowrates and fluid pressure typically spends less time in a cycle than acleaning system that has relatively low fluid flow rates and fluidpressure. The timer 212 may be programmed to vary the configurationswitching time to accommodate the cleaning program of the specificcleaning system. During a rinse, wash, or sanitize cycle of the cleaningoperation, the configuration of the aforementioned four valves ischanged at least once and preferably two or more times during eachcycle. The configuration changes of the four valves may vary betweenonce each five seconds and once each five minutes.

In a first configuration, valves 216 and 88 are opened and valves 214and 134 are closed. In this configuration, cleaning fluid enteringfitting 220 is directed through vacuum line 122 to clean the vacuumtransfer unit 10. The cleaning fluid is additionally forced through line38 to the secondary shutoff 102. The fluid cleans the secondary shutoff102 and then is expelled through drain 110.

In the second configuration, valves 214 and 134 are opened and valves216 and 88 are closed. In this configuration, cleaning fluid is forcedthrough cleaning line 130 to the spray ball 138 in order to purge thetank 14 a, 14 b, respectively. Cleaning fluid entering the tanks 14 a,14 b is then discharged from the product inlet/outlet 202 a, 202 b. Inthis manner, the tanks 14 a, 14 b and associated vacuum transfer units10, as well as vacuum lines 122, are all cleaned during a singlecleaning operation. It should be noted that the sequencing the valves88, 134, 214, and 216 between the open and closed configurations occurssubstantially simultaneously under control of the timer 212.

A further preferred embodiment of the vacuum transfer unit 10 isdepicted in FIGS. 12, 12 a, and 13. The vacuum transfer unit 10 includesa primary assembly 200 and a ball cage assembly 202.

The primary assembly 200 includes a rim 204 that is sealingly engagedwith an aperture defined in the tank 14. The rim has a central aperture206 defined therein. A domed lid 208 is suspended by engagement with therim 204 in the central aperture 206.

The domed lid 208 preferably has two pairs of depending retainers 210.

Referring to FIG. 12a, a pair of depending retainers 210 is depictedfixedly coupled to and depending from the domed lid 208. Each of thedepending retainers 210 bends inward to be more closely disposed to theball cage assembly 202. The depending retainers 210 have a retaineraperture 212 defined therein. A retaining rod 214 is passed through theretainer apertures of each of the depending retainers 210 defining apair of depending retainers 210. The retaining rod 214 may have a head216 at one end and a removable clip 218 at the other end.

Referring again to FIG. 12, the domed lid 208 has an upward directedfluid coupling. The fluid coupling 220 may be releasably coupled tovacuum and cleaning plumbing as depicted in FIGS. 1, 4, and 5. a fluidpipe 222 depends from the fluid coupling 220. A circumferential seal 224is imposed over the distal end of the fluid pipe 222. A fluid opening224 is defined in the distal end of the fluid pipe 222 and seal 224combination.

The ball cage assembly includes two components: cage 226 and ball 228.The cage 226 has a conical continuous depending wall 230. There are noapertures defined in the wall 230 between the upper margin 232 and theball opening 236 with the exception of the relatively small slits 238 aswill be described below. The upper margin 232 of the conical wall 230 isspaced apart from the domed lid 208 such that fluid may readily passover the upper margin 232 of the conical wall 230.

The conical wall 230 has an inward taper 234 defined proximate the lowermargin 235 of the conical wall 230. The lower margin 235 defines agenerally circular ball opening 236. It should be noted that thediameter of the ball opening 236 is substantially less than the diameterof the ball 228 in order to retain the ball 228 within the cage 226.

Two pair of relatively small slits 238 are defined through the conicalwall 230. The conical wall 230 is removably suspended from the domed lid208. This is accomplished by passing the retaining rod 214 through afirst slit 238 through the inside of the conical wall 230 and out thesecond slit 238 to engage the depending retainer 210.

The ball 228 may be conveniently be made in two halves, the upperspherical portion 240 being formed in a very close tolerancehemispherical shape to ensure a sealing engagement with the seal 224.The lower portion of the ball 228 need not be made with such closetolerances. A weight 242 fixedly adhered to the lower portion of theball 228 ensures that the spherical portion 240 of the ball 228 isalways upwardly disposed.

FIG. 13 depicts the vacuum transfer unit 10 of the present invention intwo operational modes. The first operational mode is during cleaning ofthe vacuum transfer unit 10 and the tank 14. In this mode, cleaningsolution and rinse are alternately pumped into the fluid coupling 220and down through the fluid pipe 222 exiting the fluid opening 225. Theball 228 drops downward within the cage 226 and is engaged in agenerally sealing engagement with the ball opening 236. In suchengagement, cleaning solution or rinse flowing into the cage 226 isprevented from flowing out the ball opening 236 and builds up within thecage 226 to cleanse/rinse both the cage 226 and the underside surfacesof the domed lid 208. The cleaning solution or rinse flows over theupper margin 232 of the conical wall 230 and into the tank 14 afterthoroughly cleansing the wetted surfaces of the vacuum transfer unit 10.

The second operation depicted in FIG. 13 is during suction filling ofthe tank 14. During such operations, a vacuum is imposed on the fluidcoupling 220. The vacuum on the tank 14 is drawn primarily via the spacedefined between the upper margin 232 of the conical wall 230 and theunderside of the domed lid 208, since the ball 228 is sealed against theball opening 236. An advantage of such design is that the weight 242holds the ball 228 into a stable engagement with the ball opening 236,thereby preventing chattering of the ball 228 against the conical wall230 during the application of suction to the fluid coupling 220.

As the product 244 rises in the tank 214, the ball 228 is floated upwardtoward the seal 224. When the product 244 rises to the level indicatedin phantom in FIG. 13 (the level depicted also in FIG. 12), thespherical portion 240 of the ball 228 comes into sealing engagement withthe seal 224, sealing off the fluid opening 225. An advantage of the endembodiment of FIGS. 12-13 is that by having a continuous conical wall230 is that any foam 246 that is on top of the product 240 is keptoutside of the cage 226 and is not drawn upward by the vacuum throughthe fluid pipe 222 prior to the sealing engagement of the ball 228 withthe seal 224. It is highly advantageous in operation, to prevent any ofthe product 244 including foam 246 from passing through the vacuumplumbing where it may enter the pump drawing the vacuum.

Various changes and modifications may be made without departing from thespirit of the invention, and all such changes and modifications arecontemplated as may come within the scope of the claims.

I claim:
 1. A method for cleaning and sanitizing a vessel and vacuumtransfer system for handling a liquid food grade product comprising thesteps of: providing a cleaning system comprising an inlet port capableof being selectively placed in fluid communication with the vessel andthe vacuum transfer system; connecting the inlet port to a source ofcleaning fluid; alternately placing the inlet port in fluidcommunication with the vessel and the vacuum transfer system accordingto a predetermined schedule, thereby allowing cleaning fluid to flowtherethrough in a predetermined series of cycles; and removing thecleaning fluid from the vessel and vacuum transfer system.
 2. The methodof claim 1, wherein the cleaning system further comprises valving meansoperably coupling said inlet port, the vessel, and the vacuum transfersystem, and wherein the step of alternately placing the inlet port influid communication with the vessel and the vacuum transfer systemcomprises operating said valving means.
 3. The method of claim 2,wherein said valving means comprises a plurality of power operablevalves, wherein said cleaning system further comprises a programmablecontrol unit in communication with each of said plurality of valves, andwherein the method further comprises the step of programming the controlunit to operate each of the plurality of valves according to apredetermined schedule.
 4. The method of claim 3, wherein said controlunit is programmed to operate each of said plurality of valves in arange from once every five seconds to once every five minutes.
 5. Themethod of claim 4, wherein said control unit is programmed to operateeach of said plurality of valves once every ten seconds.
 6. The methodof claim 1, wherein said vessel has a product outlet, wherein saidvacuum transfer system has a secondary shutoff, and wherein the step ofremoving the cleaning fluid from said vessel and said vacuum transfersystem comprises allowing the cleaning fluid to flow from the vesselthrough said product outlet and from the vacuum transfer system throughsaid secondary shutoff.